Graves Thematic Change Suggestion
As THE shotgun champion of League, Graves' general theme should be the gravelly cowboy who delivers slow but powerful shots.
With league's current implementation, Graves is essentially no different from any other rapid-firing ADC with a slightly stronger focus on AD (think Sivir or MF).
The main reason for this disjoint between thematic expectation and gameplay mainly stems from Graves' Quickdraw (dash and receive 80% attack speed) which gives you the generic +AS% steroid boost that all other ADCs have.
To further strengthen the theme of slow but powerful shotgun blasts, here's a suggested change for Quickdraw.
Quickdraw ACTIVE: Graves dashes forward and loads his gun, causing his next two attacks to become loaded shots (it's a double barreled shotgun after all). Loaded shots deal bonus physical damage, ignore a %percentage of enemy armor, and reduce the cooldown of quickdraw by 30% each if they hit an enemy champion.
This change is not meant to buff or nerf Graves, only to strengthen his own thematic niche among the crowd of quick-firing gun champions.
tl;dr, Graves should hit harder, not faster.